$fix-mqs: false !default;

@mixin respond-min($width) {
    @if $fix-mqs {
        @if $fix-mqs >= $width {
            @content;   
        }
    }
    @else {
        @media screen and (min-width: $width) {
            @content;
        }
    }
}
@mixin respond-max($width) {
    @if $fix-mqs {
        @if $fix-mqs <= $width {
            @content;   
        }
    }
    @else {
        @media screen and (max-width: $width) {
            @content;
        }
    }
}

$old-ie: false !default;

@mixin old-ie {
    @if $old-ie {
        @content;
    }
}